The invention provides a chassis structure of an electric vehicle. The chassis structure comprises a chassis main body and a battery assembly. The chassis main body comprises an upper cover plate, a lower cover plate, and a cellular holding structure between the upper cover plate and the lower cover plate. The cellular holding structure comprises a plurality of hollow cell units. The battery assembly comprises a plurality of battery cells. The battery cells are held in the cell units. The periphery of the cellular holding structure is also provided with a support. The support comprises a pairof opposite vertical beams. The pair of opposite vertical beams comprise a pair of parallel main body portions and two pairs of opposite extension portions formed by extending two ends of the pair ofmain body portions. The pair of main body portions are respectively arranged on two sides of the cellular holding structure.